Critical CSS Extractor
Fetch a page and extract CSS rules that match elements in its DOM.
How to Extract Critical CSS?
- Enter the URL of the page you want to optimize.
- Click Extract to fetch the page and analyze CSS.
- View the extracted critical (above-the-fold) CSS rules.
- Inline this CSS in your page's <head> for faster rendering.
- Load the full CSS asynchronously for better performance.
Critical CSS Extractor — Improve Page Speed
Extract the above-the-fold CSS needed to render your page's initial view instantly. Critical CSS is the minimal set of styles required to display content visible without scrolling. Inlining it directly in your HTML <head> eliminates render-blocking stylesheet requests and dramatically improves perceived load time and Core Web Vitals scores.
Why Critical CSS Matters
- Faster First Contentful Paint (FCP) — Users see styled content in milliseconds, not after the full CSS loads
- Better Lighthouse / CrUX Scores — Reduces render-blocking resources, a key PageSpeed metric
- Improved SEO — Google uses Core Web Vitals as a ranking signal
Implementation
Inline the extracted CSS in a <style> tag in your <head>, then load the full stylesheet asynchronously using rel="preload" or a JavaScript loader.
Frequently Asked Questions
What is critical CSS?
Critical CSS is the minimal subset of your stylesheet needed to render the above-the-fold content of a page — what the user sees without scrolling. Inlining it eliminates a render-blocking network request and makes pages appear to load faster.
How do I use the extracted critical CSS?
Copy the output and paste it inside a <style> tag in your HTML <head>. Then load your full CSS file asynchronously: add rel="preload" as="style" to your <link> tag and use a JS snippet to switch it to rel="stylesheet" after load.
Will the extracted CSS cover my entire page?
No — critical CSS only covers above-the-fold content visible at the specified viewport. Styles for below-the-fold content and interactive elements are intentionally excluded; they should still be loaded via your full stylesheet.
Does this tool work with CSS-in-JS or Tailwind?
This tool works by fetching the rendered page and analyzing its computed styles. It works regardless of how CSS is generated — traditional stylesheets, Tailwind, CSS-in-JS — as long as the page URL is publicly accessible.
